From aab9aa8a2e683106cd1a654b7cc9ce5bcad8203a Mon Sep 17 00:00:00 2001 From: Nick Craig-Wood Date: Sat, 1 Aug 2020 15:36:20 +0100 Subject: [PATCH] js: add experimental interface for integrating rclone into browsers This works by compiling rclone to wasm and exporting the RC api to javascript. --- fs/rc/js/.gitignore | 1 + fs/rc/js/Makefile | 5 + fs/rc/js/README.md | 25 ++ fs/rc/js/index.html | 11 + fs/rc/js/loader.js | 36 +++ fs/rc/js/main.go | 145 +++++++++++ fs/rc/js/serve.go | 19 ++ fs/rc/js/wasm_exec.js | 588 ++++++++++++++++++++++++++++++++++++++++++ 8 files changed, 830 insertions(+) create mode 100644 fs/rc/js/.gitignore create mode 100644 fs/rc/js/Makefile create mode 100644 fs/rc/js/README.md create mode 100644 fs/rc/js/index.html create mode 100644 fs/rc/js/loader.js create mode 100644 fs/rc/js/main.go create mode 100644 fs/rc/js/serve.go create mode 100644 fs/rc/js/wasm_exec.js diff --git a/fs/rc/js/.gitignore b/fs/rc/js/.gitignore new file mode 100644 index 000000000..19e1bced9 --- /dev/null +++ b/fs/rc/js/.gitignore @@ -0,0 +1 @@ +*.wasm diff --git a/fs/rc/js/Makefile b/fs/rc/js/Makefile new file mode 100644 index 000000000..9ada0fb55 --- /dev/null +++ b/fs/rc/js/Makefile @@ -0,0 +1,5 @@ +build: + GOARCH=wasm GOOS=js go build -o rclone.wasm + +serve: build + go run serve.go diff --git a/fs/rc/js/README.md b/fs/rc/js/README.md new file mode 100644 index 000000000..4a546d228 --- /dev/null +++ b/fs/rc/js/README.md @@ -0,0 +1,25 @@ +# Rclone as WASM + +This directory contains files to use the rclone rc as a library in the browser. + +This works by compiling rclone to WASM and loading that in via javascript. + +This contains the following files + +- `index.html` - test web page to load the module +- `loader.js` - java script to load the module - see here for usage +- `main.go` - main go code exporting the rclone rc +- `Makefile` - test makefile +- `README.md` - this readme +- `serve.go` - test program to serve the web page +- `wasm_exec.js` - interface code from the go source - don't edit + +## Compiling + +This can be compiled by using `make` or alternatively `GOARCH=wasm GOOS=js go build -o rclone.wasm` + +## Running + +Run the test server with `make serve` and examine the page at +http://localhost:3000/ - look at the javascript console and look at +the end of `loader.js` for how that works. diff --git a/fs/rc/js/index.html b/fs/rc/js/index.html new file mode 100644 index 000000000..f1e202ffe --- /dev/null +++ b/fs/rc/js/index.html @@ -0,0 +1,11 @@ + + + + + Rclone + + + +

Welcome to rclone - check the console

+ + diff --git a/fs/rc/js/loader.js b/fs/rc/js/loader.js new file mode 100644 index 000000000..126516f4b --- /dev/null +++ b/fs/rc/js/loader.js @@ -0,0 +1,36 @@ +var rc; +var rcValidResolve +var rcValid = new Promise(resolve => { + rcValidResolve = resolve +}); + +var script = document.createElement('script'); +script.src = "wasm_exec.js"; +script.onload = function () { + if (!WebAssembly.instantiateStreaming) { // polyfill + WebAssembly.instantiateStreaming = async (resp, importObject) => { + const source = await (await resp).arrayBuffer(); + return await WebAssembly.instantiate(source, importObject); + }; + } + const go = new Go(); + WebAssembly.instantiateStreaming(fetch("rclone.wasm"), go.importObject).then((result) => { + go.run(result.instance); + }); + +}; +document.head.appendChild(script); + +rcValid.then(() => { + // Some examples of using the rc call + // + // The rc call takes two parameters, method and input object and + // returns an output object. + // + // If the output object has an "error" and a "status" then it is an + // error (it would be nice to signal this out of band). + console.log("core/version", rc("core/version", null)) + console.log("core/version", rc("rc/noop", {"string":"one",number:2})) + console.log("core/version", rc("operations/mkdir", {"fs":":memory:","remote":"bucket"})) + console.log("core/version", rc("operations/list", {"fs":":memory:","remote":"bucket"})) +}) diff --git a/fs/rc/js/main.go b/fs/rc/js/main.go new file mode 100644 index 000000000..53a1026f0 --- /dev/null +++ b/fs/rc/js/main.go @@ -0,0 +1,145 @@ +// Rclone as a wasm library +// +// This library exports the core rc functionality + +// +build js + +package main + +import ( + "context" + "encoding/json" + "log" + "net/http" + "runtime" + "syscall/js" + + "github.com/pkg/errors" + "github.com/rclone/rclone/fs" + "github.com/rclone/rclone/fs/rc" + + // Core functionality we need + _ "github.com/rclone/rclone/fs/operations" + _ "github.com/rclone/rclone/fs/sync" + + // _ "github.com/rclone/rclone/backend/all" // import all backends + + // Backends + _ "github.com/rclone/rclone/backend/memory" +) + +var ( + document js.Value + jsJSON js.Value +) + +func getElementById(name string) js.Value { + node := document.Call("getElementById", name) + if node.IsUndefined() { + log.Fatalf("Couldn't find element %q", name) + } + return node +} + +func time() int { + return js.Global().Get("Date").New().Call("getTime").Int() +} + +func paramToValue(in rc.Params) (out js.Value) { + return js.Value{} +} + +// errorValue turns an error into a js.Value +func errorValue(method string, in js.Value, err error) js.Value { + fs.Errorf(nil, "rc: %q: error: %v", method, err) + // Adjust the error return for some well known errors + errOrig := errors.Cause(err) + status := http.StatusInternalServerError + switch { + case errOrig == fs.ErrorDirNotFound || errOrig == fs.ErrorObjectNotFound: + status = http.StatusNotFound + case rc.IsErrParamInvalid(err) || rc.IsErrParamNotFound(err): + status = http.StatusBadRequest + } + return js.ValueOf(map[string]interface{}{ + "status": status, + "error": err.Error(), + "input": in, + "path": method, + }) +} + +// rcCallback is a callback for javascript to access the api +// +// FIXME should this should return a promise so we can return errors properly? +func rcCallback(this js.Value, args []js.Value) interface{} { + ctx := context.Background() // FIXME + log.Printf("rcCallback: this=%v args=%v", this, args) + + if len(args) != 2 { + return errorValue("", js.Undefined(), errors.New("need two parameters to rc call")) + } + method := args[0].String() + inRaw := args[1] + var in = rc.Params{} + switch inRaw.Type() { + case js.TypeNull: + case js.TypeObject: + inJSON := jsJSON.Call("stringify", inRaw).String() + err := json.Unmarshal([]byte(inJSON), &in) + if err != nil { + return errorValue(method, inRaw, errors.Wrap(err, "couldn't unmarshal input")) + } + default: + return errorValue(method, inRaw, errors.New("in parameter must be null or object")) + } + + call := rc.Calls.Get(method) + if call == nil { + return errorValue(method, inRaw, errors.Errorf("method %q not found", method)) + } + + out, err := call.Fn(ctx, in) + if err != nil { + return errorValue(method, inRaw, errors.Wrap(err, "method call failed")) + } + if out == nil { + return nil + } + var out2 map[string]interface{} + err = rc.Reshape(&out2, out) + if err != nil { + return errorValue(method, inRaw, errors.Wrap(err, "result reshape failed")) + } + + return js.ValueOf(out2) +} + +func main() { + log.Printf("Running on goos/goarch = %s/%s", runtime.GOOS, runtime.GOARCH) + if js.Global().IsUndefined() { + log.Fatalf("Didn't find Global - not running in browser") + } + document = js.Global().Get("document") + if document.IsUndefined() { + log.Fatalf("Didn't find document - not running in browser") + } + + jsJSON = js.Global().Get("JSON") + if jsJSON.IsUndefined() { + log.Fatalf("can't find JSON") + } + + // Set rc + js.Global().Set("rc", js.FuncOf(rcCallback)) + + // Signal that it is valid + rcValidResolve := js.Global().Get("rcValidResolve") + if rcValidResolve.IsUndefined() { + log.Fatalf("Didn't find rcValidResolve") + } + rcValidResolve.Invoke() + + // Wait forever + select {} +} diff --git a/fs/rc/js/serve.go b/fs/rc/js/serve.go new file mode 100644 index 000000000..ee9a6b783 --- /dev/null +++ b/fs/rc/js/serve.go @@ -0,0 +1,19 @@ +//+build none + +package main + +import ( + "fmt" + "log" + "mime" + "net/http" +) + +func main() { + mime.AddExtensionType(".wasm", "application/wasm") + mime.AddExtensionType(".js", "application/javascript") + mux := http.NewServeMux() + mux.Handle("/", http.FileServer(http.Dir("."))) + fmt.Printf("Serving on http://localhost:3000/\n") + log.Fatal(http.ListenAndServe(":3000", mux)) +} diff --git a/fs/rc/js/wasm_exec.js b/fs/rc/js/wasm_exec.js new file mode 100644 index 000000000..8501ae7cd --- /dev/null +++ b/fs/rc/js/wasm_exec.js @@ -0,0 +1,588 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +(() => { + // Map multiple JavaScript environments to a single common API, + // preferring web standards over Node.js API. + // + // Environments considered: + // - Browsers + // - Node.js + // - Electron + // - Parcel + + if (typeof global !== "undefined") { + // global already exists + } else if (typeof window !== "undefined") { + window.global = window; + } else if (typeof self !== "undefined") { + self.global = self; + } else { + throw new Error("cannot export Go (neither global, window nor self is defined)"); + } + + if (!global.require && typeof require !== "undefined") { + global.require = require; + } + + if (!global.fs && global.require) { + const fs = require("fs"); + if (Object.keys(fs) !== 0) { + global.fs = fs; + } + } + + const enosys = () => { + const err = new Error("not implemented"); + err.code = "ENOSYS"; + return err; + }; + + if (!global.fs) { + let outputBuf = ""; + global.fs = { + constants: { O_WRONLY: -1, O_RDWR: -1, O_CREAT: -1, O_TRUNC: -1, O_APPEND: -1, O_EXCL: -1 }, // unused + writeSync(fd, buf) { + outputBuf += decoder.decode(buf); + const nl = outputBuf.lastIndexOf("\n"); + if (nl != -1) { + console.log(outputBuf.substr(0, nl)); + outputBuf = outputBuf.substr(nl + 1); + } + return buf.length; + }, + write(fd, buf, offset, length, position, callback) { + if (offset !== 0 || length !== buf.length || position !== null) { + callback(enosys()); + return; + } + const n = this.writeSync(fd, buf); + callback(null, n); + }, + chmod(path, mode, callback) { callback(enosys()); }, + chown(path, uid, gid, callback) { callback(enosys()); }, + close(fd, callback) { callback(enosys()); }, + fchmod(fd, mode, callback) { callback(enosys()); }, + fchown(fd, uid, gid, callback) { callback(enosys()); }, + fstat(fd, callback) { callback(enosys()); }, + fsync(fd, callback) { callback(null); }, + ftruncate(fd, length, callback) { callback(enosys()); }, + lchown(path, uid, gid, callback) { callback(enosys()); }, + link(path, link, callback) { callback(enosys()); }, + lstat(path, callback) { callback(enosys()); }, + mkdir(path, perm, callback) { callback(enosys()); }, + open(path, flags, mode, callback) { callback(enosys()); }, + read(fd, buffer, offset, length, position, callback) { callback(enosys()); }, + readdir(path, callback) { callback(enosys()); }, + readlink(path, callback) { callback(enosys()); }, + rename(from, to, callback) { callback(enosys()); }, + rmdir(path, callback) { callback(enosys()); }, + stat(path, callback) { callback(enosys()); }, + symlink(path, link, callback) { callback(enosys()); }, + truncate(path, length, callback) { callback(enosys()); }, + unlink(path, callback) { callback(enosys()); }, + utimes(path, atime, mtime, callback) { callback(enosys()); }, + }; + } + + if (!global.process) { + global.process = { + getuid() { return -1; }, + getgid() { return -1; }, + geteuid() { return -1; }, + getegid() { return -1; }, + getgroups() { throw enosys(); }, + pid: -1, + ppid: -1, + umask() { throw enosys(); }, + cwd() { throw enosys(); }, + chdir() { throw enosys(); }, + } + } + + if (!global.crypto) { + const nodeCrypto = require("crypto"); + global.crypto = { + getRandomValues(b) { + nodeCrypto.randomFillSync(b); + }, + }; + } + + if (!global.performance) { + global.performance = { + now() { + const [sec, nsec] = process.hrtime(); + return sec * 1000 + nsec / 1000000; + }, + }; + } + + if (!global.TextEncoder) { + global.TextEncoder = require("util").TextEncoder; + } + + if (!global.TextDecoder) { + global.TextDecoder = require("util").TextDecoder; + } + + // End of polyfills for common API. + + const encoder = new TextEncoder("utf-8"); + const decoder = new TextDecoder("utf-8"); + + global.Go = class { + constructor() { + this.argv = ["js"]; + this.env = {}; + this.exit = (code) => { + if (code !== 0) { + console.warn("exit code:", code); + } + }; + this._exitPromise = new Promise((resolve) => { + this._resolveExitPromise = resolve; + }); + this._pendingEvent = null; + this._scheduledTimeouts = new Map(); + this._nextCallbackTimeoutID = 1; + + const setInt64 = (addr, v) => { + this.mem.setUint32(addr + 0, v, true); + this.mem.setUint32(addr + 4, Math.floor(v / 4294967296), true); + } + + const getInt64 = (addr) => { + const low = this.mem.getUint32(addr + 0, true); + const high = this.mem.getInt32(addr + 4, true); + return low + high * 4294967296; + } + + const loadValue = (addr) => { + const f = this.mem.getFloat64(addr, true); + if (f === 0) { + return undefined; + } + if (!isNaN(f)) { + return f; + } + + const id = this.mem.getUint32(addr, true); + return this._values[id]; + } + + const storeValue = (addr, v) => { + const nanHead = 0x7FF80000; + + if (typeof v === "number" && v !== 0) { + if (isNaN(v)) { + this.mem.setUint32(addr + 4, nanHead, true); + this.mem.setUint32(addr, 0, true); + return; + } + this.mem.setFloat64(addr, v, true); + return; + } + + if (v === undefined) { + this.mem.setFloat64(addr, 0, true); + return; + } + + let id = this._ids.get(v); + if (id === undefined) { + id = this._idPool.pop(); + if (id === undefined) { + id = this._values.length; + } + this._values[id] = v; + this._goRefCounts[id] = 0; + this._ids.set(v, id); + } + this._goRefCounts[id]++; + let typeFlag = 0; + switch (typeof v) { + case "object": + if (v !== null) { + typeFlag = 1; + } + break; + case "string": + typeFlag = 2; + break; + case "symbol": + typeFlag = 3; + break; + case "function": + typeFlag = 4; + break; + } + this.mem.setUint32(addr + 4, nanHead | typeFlag, true); + this.mem.setUint32(addr, id, true); + } + + const loadSlice = (addr) => { + const array = getInt64(addr + 0); + const len = getInt64(addr + 8); + return new Uint8Array(this._inst.exports.mem.buffer, array, len); + } + + const loadSliceOfValues = (addr) => { + const array = getInt64(addr + 0); + const len = getInt64(addr + 8); + const a = new Array(len); + for (let i = 0; i < len; i++) { + a[i] = loadValue(array + i * 8); + } + return a; + } + + const loadString = (addr) => { + const saddr = getInt64(addr + 0); + const len = getInt64(addr + 8); + return decoder.decode(new DataView(this._inst.exports.mem.buffer, saddr, len)); + } + + const timeOrigin = Date.now() - performance.now(); + this.importObject = { + go: { + // Go's SP does not change as long as no Go code is running. Some operations (e.g. calls, getters and setters) + // may synchronously trigger a Go event handler. This makes Go code get executed in the middle of the imported + // function. A goroutine can switch to a new stack if the current stack is too small (see morestack function). + // This changes the SP, thus we have to update the SP used by the imported function. + + // func wasmExit(code int32) + "runtime.wasmExit": (sp) => { + const code = this.mem.getInt32(sp + 8, true); + this.exited = true; + delete this._inst; + delete this._values; + delete this._goRefCounts; + delete this._ids; + delete this._idPool; + this.exit(code); + }, + + // func wasmWrite(fd uintptr, p unsafe.Pointer, n int32) + "runtime.wasmWrite": (sp) => { + const fd = getInt64(sp + 8); + const p = getInt64(sp + 16); + const n = this.mem.getInt32(sp + 24, true); + fs.writeSync(fd, new Uint8Array(this._inst.exports.mem.buffer, p, n)); + }, + + // func resetMemoryDataView() + "runtime.resetMemoryDataView": (sp) => { + this.mem = new DataView(this._inst.exports.mem.buffer); + }, + + // func nanotime1() int64 + "runtime.nanotime1": (sp) => { + setInt64(sp + 8, (timeOrigin + performance.now()) * 1000000); + }, + + // func walltime1() (sec int64, nsec int32) + "runtime.walltime1": (sp) => { + const msec = (new Date).getTime(); + setInt64(sp + 8, msec / 1000); + this.mem.setInt32(sp + 16, (msec % 1000) * 1000000, true); + }, + + // func scheduleTimeoutEvent(delay int64) int32 + "runtime.scheduleTimeoutEvent": (sp) => { + const id = this._nextCallbackTimeoutID; + this._nextCallbackTimeoutID++; + this._scheduledTimeouts.set(id, setTimeout( + () => { + this._resume(); + while (this._scheduledTimeouts.has(id)) { + // for some reason Go failed to register the timeout event, log and try again + // (temporary workaround for https://github.com/golang/go/issues/28975) + console.warn("scheduleTimeoutEvent: missed timeout event"); + this._resume(); + } + }, + getInt64(sp + 8) + 1, // setTimeout has been seen to fire up to 1 millisecond early + )); + this.mem.setInt32(sp + 16, id, true); + }, + + // func clearTimeoutEvent(id int32) + "runtime.clearTimeoutEvent": (sp) => { + const id = this.mem.getInt32(sp + 8, true); + clearTimeout(this._scheduledTimeouts.get(id)); + this._scheduledTimeouts.delete(id); + }, + + // func getRandomData(r []byte) + "runtime.getRandomData": (sp) => { + crypto.getRandomValues(loadSlice(sp + 8)); + }, + + // func finalizeRef(v ref) + "syscall/js.finalizeRef": (sp) => { + const id = this.mem.getUint32(sp + 8, true); + this._goRefCounts[id]--; + if (this._goRefCounts[id] === 0) { + const v = this._values[id]; + this._values[id] = null; + this._ids.delete(v); + this._idPool.push(id); + } + }, + + // func stringVal(value string) ref + "syscall/js.stringVal": (sp) => { + storeValue(sp + 24, loadString(sp + 8)); + }, + + // func valueGet(v ref, p string) ref + "syscall/js.valueGet": (sp) => { + const result = Reflect.get(loadValue(sp + 8), loadString(sp + 16)); + sp = this._inst.exports.getsp(); // see comment above + storeValue(sp + 32, result); + }, + + // func valueSet(v ref, p string, x ref) + "syscall/js.valueSet": (sp) => { + Reflect.set(loadValue(sp + 8), loadString(sp + 16), loadValue(sp + 32)); + }, + + // func valueDelete(v ref, p string) + "syscall/js.valueDelete": (sp) => { + Reflect.deleteProperty(loadValue(sp + 8), loadString(sp + 16)); + }, + + // func valueIndex(v ref, i int) ref + "syscall/js.valueIndex": (sp) => { + storeValue(sp + 24, Reflect.get(loadValue(sp + 8), getInt64(sp + 16))); + }, + + // valueSetIndex(v ref, i int, x ref) + "syscall/js.valueSetIndex": (sp) => { + Reflect.set(loadValue(sp + 8), getInt64(sp + 16), loadValue(sp + 24)); + }, + + // func valueCall(v ref, m string, args []ref) (ref, bool) + "syscall/js.valueCall": (sp) => { + try { + const v = loadValue(sp + 8); + const m = Reflect.get(v, loadString(sp + 16)); + const args = loadSliceOfValues(sp + 32); + const result = Reflect.apply(m, v, args); + sp = this._inst.exports.getsp(); // see comment above + storeValue(sp + 56, result); + this.mem.setUint8(sp + 64, 1); + } catch (err) { + storeValue(sp + 56, err); + this.mem.setUint8(sp + 64, 0); + } + }, + + // func valueInvoke(v ref, args []ref) (ref, bool) + "syscall/js.valueInvoke": (sp) => { + try { + const v = loadValue(sp + 8); + const args = loadSliceOfValues(sp + 16); + const result = Reflect.apply(v, undefined, args); + sp = this._inst.exports.getsp(); // see comment above + storeValue(sp + 40, result); + this.mem.setUint8(sp + 48, 1); + } catch (err) { + storeValue(sp + 40, err); + this.mem.setUint8(sp + 48, 0); + } + }, + + // func valueNew(v ref, args []ref) (ref, bool) + "syscall/js.valueNew": (sp) => { + try { + const v = loadValue(sp + 8); + const args = loadSliceOfValues(sp + 16); + const result = Reflect.construct(v, args); + sp = this._inst.exports.getsp(); // see comment above + storeValue(sp + 40, result); + this.mem.setUint8(sp + 48, 1); + } catch (err) { + storeValue(sp + 40, err); + this.mem.setUint8(sp + 48, 0); + } + }, + + // func valueLength(v ref) int + "syscall/js.valueLength": (sp) => { + setInt64(sp + 16, parseInt(loadValue(sp + 8).length)); + }, + + // valuePrepareString(v ref) (ref, int) + "syscall/js.valuePrepareString": (sp) => { + const str = encoder.encode(String(loadValue(sp + 8))); + storeValue(sp + 16, str); + setInt64(sp + 24, str.length); + }, + + // valueLoadString(v ref, b []byte) + "syscall/js.valueLoadString": (sp) => { + const str = loadValue(sp + 8); + loadSlice(sp + 16).set(str); + }, + + // func valueInstanceOf(v ref, t ref) bool + "syscall/js.valueInstanceOf": (sp) => { + this.mem.setUint8(sp + 24, (loadValue(sp + 8) instanceof loadValue(sp + 16)) ? 1 : 0); + }, + + // func copyBytesToGo(dst []byte, src ref) (int, bool) + "syscall/js.copyBytesToGo": (sp) => { + const dst = loadSlice(sp + 8); + const src = loadValue(sp + 32); + if (!(src instanceof Uint8Array || src instanceof Uint8ClampedArray)) { + this.mem.setUint8(sp + 48, 0); + return; + } + const toCopy = src.subarray(0, dst.length); + dst.set(toCopy); + setInt64(sp + 40, toCopy.length); + this.mem.setUint8(sp + 48, 1); + }, + + // func copyBytesToJS(dst ref, src []byte) (int, bool) + "syscall/js.copyBytesToJS": (sp) => { + const dst = loadValue(sp + 8); + const src = loadSlice(sp + 16); + if (!(dst instanceof Uint8Array || dst instanceof Uint8ClampedArray)) { + this.mem.setUint8(sp + 48, 0); + return; + } + const toCopy = src.subarray(0, dst.length); + dst.set(toCopy); + setInt64(sp + 40, toCopy.length); + this.mem.setUint8(sp + 48, 1); + }, + + "debug": (value) => { + console.log(value); + }, + } + }; + } + + async run(instance) { + this._inst = instance; + this.mem = new DataView(this._inst.exports.mem.buffer); + this._values = [ // JS values that Go currently has references to, indexed by reference id + NaN, + 0, + null, + true, + false, + global, + this, + ]; + this._goRefCounts = new Array(this._values.length).fill(Infinity); // number of references that Go has to a JS value, indexed by reference id + this._ids = new Map([ // mapping from JS values to reference ids + [0, 1], + [null, 2], + [true, 3], + [false, 4], + [global, 5], + [this, 6], + ]); + this._idPool = []; // unused ids that have been garbage collected + this.exited = false; // whether the Go program has exited + + // Pass command line arguments and environment variables to WebAssembly by writing them to the linear memory. + let offset = 4096; + + const strPtr = (str) => { + const ptr = offset; + const bytes = encoder.encode(str + "\0"); + new Uint8Array(this.mem.buffer, offset, bytes.length).set(bytes); + offset += bytes.length; + if (offset % 8 !== 0) { + offset += 8 - (offset % 8); + } + return ptr; + }; + + const argc = this.argv.length; + + const argvPtrs = []; + this.argv.forEach((arg) => { + argvPtrs.push(strPtr(arg)); + }); + argvPtrs.push(0); + + const keys = Object.keys(this.env).sort(); + keys.forEach((key) => { + argvPtrs.push(strPtr(`${key}=${this.env[key]}`)); + }); + argvPtrs.push(0); + + const argv = offset; + argvPtrs.forEach((ptr) => { + this.mem.setUint32(offset, ptr, true); + this.mem.setUint32(offset + 4, 0, true); + offset += 8; + }); + + this._inst.exports.run(argc, argv); + if (this.exited) { + this._resolveExitPromise(); + } + await this._exitPromise; + } + + _resume() { + if (this.exited) { + throw new Error("Go program has already exited"); + } + this._inst.exports.resume(); + if (this.exited) { + this._resolveExitPromise(); + } + } + + _makeFuncWrapper(id) { + const go = this; + return function () { + const event = { id: id, this: this, args: arguments }; + go._pendingEvent = event; + go._resume(); + return event.result; + }; + } + } + + if ( + global.require && + global.require.main === module && + global.process && + global.process.versions && + !global.process.versions.electron + ) { + if (process.argv.length < 3) { + console.error("usage: go_js_wasm_exec [wasm binary] [arguments]"); + process.exit(1); + } + + const go = new Go(); + go.argv = process.argv.slice(2); + go.env = Object.assign({ TMPDIR: require("os").tmpdir() }, process.env); + go.exit = process.exit; + WebAssembly.instantiate(fs.readFileSync(process.argv[2]), go.importObject).then((result) => { + process.on("exit", (code) => { // Node.js exits if no event handler is pending + if (code === 0 && !go.exited) { + // deadlock, make Go print error and stack traces + go._pendingEvent = { id: 0 }; + go._resume(); + } + }); + return go.run(result.instance); + }).catch((err) => { + console.error(err); + process.exit(1); + }); + } +})();